Question | Answer |
what attaches the ovaries to the body wall? | the broad ligament |
what is the mesovarium? | the area of the broad ligament that supports the ovaries |
what shape are the ovaries? | broad bean |
what size are the follicles when they release the oocyte? | 40-50mm |
wheres the oocyte released from? | the ovulation fossa |
where in the horse can the overies be found? | around the 3rd and 4th lumber vertebrae more lateral than would be found in a cow |
how far does the stallions sperm need to swim? | 20-30 cm |
Early oestrus | |
mid oestrus | |
Oviduct pippilae | |
how long is the horses cervix? | 4-10 centimeters |
how wide is the horses cervix? | 2-4 cm |
what can be a problem with an older maiden mares cervix? | it can become fibroses |
end oestrus | |
dioestrus | |
Healthy endometrium | |
How is a cervical smear carried out? | the perineum is cleaned up, the swab is taken of their cervix, and rolled onto a clean dry slide. The slide is fixed and then stained usually with diff quick. |
what is vesicovagina reflux? | urine pooling |
how may vesicovagina reflux be treated? | This may be transient or require surgical treatment. some may become fertile just by laving the urine out. the surgeries include; caslick, urethral extension or urethroplasty etc |
how should a hyman be approached? | break it down manually then step back and lavage, very smelly! |
whats the most common cause of bleeding in the mare? | varocus veins in the vestibulo-vaginal junction |
how are varocus veins in the vestibulo-vaginal junction treated? | leave alone if mild diathermy if sever |
what is winking? | when the horse exposes her clitoral fossa. |
what type of culture should be done on the clitoris? | microaerophilic/aerobic culture |
what bacteria may live on the clitoris? | ontagious equine metritis organisms, pseudamonus aeruginosa and klebsiella pneumonia 1, 2 and 5. |
where in relation to the pelvis should the vagina sit? | paralel to the tuber ischium |
whats the most common reason for mares getting pneumovagina? | they get old, their vagina rises above the tuber ischium which causes it to stick out further than the anus causing it to open. |
How is pneumovagina best treated? | caslick |
how can pneumovagina be definitively diagnosed? | ultrasound the uterus for air inside it |
what can a low caslick cause? | urine retention |
when carrying out a breeding soundness exam what history should be taken? | how many foals has the horse had, how many have lived and how many have died, whats the age, breed and purpose, last date of parturition, difficulties with parturition, number of previous matings, which stallion, when was the last oestrus, how long is the oestrous cycle, previous exams exams and treatments and vaccination/worming status. |
whats included in a gynaecological exam? | examination of the vulval seal, a clitoral swab, examine the vagina and cervix, endometrial bacteriology and cytology (possibly biopsy), a rectal exam, endoscopic exam, ultrasound exam and a blood sample for hormone and chromosome analysis. |
what are the most important things on an equines reproduction? | -increasing daylight length (optimal breeding will start on the 15th of february to get a horse born on the 1st of jan) -Temperature -health body condition -food supply Increasing daylight length is the most important! |
what are the phases of a horses reproductive cycle? | oestrus and di oestrus |
what are alternative names for oestrus and diestrous? | oestrus= follicular phase dioestrus= luteal phase |
whats a horses average cycle length? | 20-23 days |
whats the average oestrus length? | 4-7 days |
how long do oestrus behaviours tend to last? | 24-48 hours |
pre ovulation follicle | |
Corpus luteum | |
whats the scoring system for equine oestrus behaviour? | 0-mare aggressive and kicking 1- mare showing interest in the teaser 2- mare winks (everts clitoris) 3- mare is quickly interested in the teaser, winks and pees 4- mare stands with legs apart and passes a cloudy urine |
why might a teasing give false results? | mare is nervous (maiden) or has a foal at foot. |
when is the mare best mated? | 48 hours before or 6 hours after ovulation. |
How does melanin control the hypothalamus? | The pineal gland produces melatonin when there is a reduction in light, it inhibits the production of GnRH in the hypothalamus |
How does GnRH act? | causes release of eCG, LH and FSH from the anterior lobe of the pituitary gland |
What is FSH's job? | stimulate growth of the follicles |
How does LH work an when does it peak? | final maturation of the follicles and peaks about 24 48h post ovulation |
What produces oestrogen, when does it peak and whats its job? | Oestrogen is produced by the follicle and peaks 12-36hours before ovulation. It is responsible for oestrous behavior. |
What produces progesterone, whats its job and when does it peak? | Progesterone is produced by the CL following ovulation. There is a rapid rise post ovulation and then a sharp decline post luteolysis. Progesterone inhibits oestrous behavior and prepares the uterus for pregnancy. |
How do the ovaries feel and look on U/S at oestrus? | Fist size, with many soft follicles 2-3 cm. The pre ovulatory follicle may be seen on U/S near to the ovulation fossa. |
What do the ovaries feel like in dioestrus and how do they appear on u/s? | The ovary is fist size, there will be many follicles at about 3 cm, on u/s CL can be seen |
What does the ovaries feel like in anoestrus and what do they look like on u/s? | They feel small and there will be no CL on U/s |
How can the mare be stimulated with lights and how long would it be expected for this to work? | To do this the horse needs 16 hours of light and 8 hours of darkness at 200W. Horsey people call this putting the mare under lights. This will take 8-10 weeks to take affect in the horse. Mares must be in good condition. At the end of the light period a synthetic progestogen (regumate) may be used for 10-15 days. 10 days later the mare should come into oestrus and ovulate. |
How can the horse be stimulated to ovulate within 24-48 hours? | Give hCG (Chorulon)when the follicle is 35mm, the mare should ovulate 24-48 hours later. |
What drugs can be used to shorten the luteal phase? | Prostoglandins may be used 5 days post ovulation |
What are the three methods of pregnancy diagnosis? | -Assessing the mares behavior daily -Measuring hormone levels in the blood/urine of the mare -rectal palpation and U/S |
When can a pregnancy be diagnosed on behavior alone? | after 15-19 days of the mare not returning to heat |
what hormones can be measured for pregnancy diagnosis and when do these start to work from? | progesterone, eCG and estrogen, if progesterone and eCG are high 18-20 days this may indicate pregnancy, but may remain high if CL remains due to pathology, oestrogen is high roughtly 100 days post fertilization |
When may a U/S or rectal be used to diagnose pregnancy? | most reliable, at day 11 may see a 5-8mm follicle, day 16 the uterus becomes more turgid, and on day 30 the follicle is about the size of a billiard ball, The most common time to perform the first exam is 14-16 days |
When should a pregnancy be scanned for twins and what are the options at each stage? | The ideal scaning dates are: 1) day 14-16 (should massage a twin pregnancy away) 2) day 25-28 (up to 30 days can crush or inject with progstaglandin) 3) day 34 (after this a twin prgenancy can only be aborted by a trans vaginal needle puncture) |
When will an embryo develop a heart beat? | 23 days |
if a mare is left with twins what is the typical progression? | abortion 7-8 months and no return to oestrus for at least 12 months |
What is the first challenge the embryo may encounter in the uterus? | Some mares get a post mating endometritis caused by the sperm, usually it only lasts 24-36 hours, if it lasts >48 hours its likely to kill the embryo, usually this occurs before 5.5 days |
What are reasons for fluid accumulating in the uterus? | the mare naturally produces too much fluid, reduced myometrial contractions, insufficient drainage, large uterus hanging over the pelvic brim and a tight cervix. |
how can post mating endomeritis be treated? | giving oxytocin (an initial IV does 4-6 hours after fertilization followed by an IM does), after 12 hours prostaglandin may be given and the uterus can be flushed with 2-3 liters of warm saline until clear fluid comes back (4-6 hours after mating). Some people will use a broad spectrum antibiotics |
What are the three areas of a sperm? | middle piece, head and tail |
How many chromosomes does a horse have? | 32 |
how many days does it take for a sperm to be produced? | 55-57 |
What are the three fractions of sperm | preejaculatory, sperm rich and gel/sperm poor fraction. |
what are the pros an cons of AI? | Pros; reduces the risk of the mare getting damaged, it reduces the likely hood of STD, there is less inflammation and an increase in the number of stallions to choose from. cons; unable to race, it requires skills, increased cost, increased paper work, some semen cannot cope with the traveling and some mares are hard to work out what their cycle is doing. |
What are the semen choice options for AI? | Liquid (fresh or chilled) fresh (extended or raw) |
How should an artificial vagina be prepared for AI? | at a temperature of 43-45degs C, a non spermicidal lubricant should be used, between use they should be washed thoroughly with 70% alcohol. |
what three things can destroy fresh semen? | Light chemicals and water |
what are the 8 stages of collecting semen? | -filtering (to remove debris and the gel fraction) -extending -centrifugation -Evaluation -devision -identification -cooling -shipping |
what color should semen be? | white, grey and other colours indicate contamination |
How should semen be evaluated? | -amount (50-70ml normal) -colour (white nomal) -pH -% motility -sperm concentrations -sperm morphology |
whats the normal sperm concentrations? | 100-800 million per ml |
how is sperm concentration measured? | using a haemocytometer. |
what indicates the sperm is dead? | its colour, pink=dead abnormal tail/morphology= dead |
How should semen be stored | at room temperature if un extended -after 6 hours at 18-22 degrees it may be chilled (4-6degrees) or frozen (-196degrees). Sperm can last chilled for 48 hours. |
what may be used for extension of semen? | egg yolk or skim milk |
how many sperm are needed to fertilize the horse? | 300-500 |
what are the two insemination techniques? | deep insemination or just deposition in the uterine body. |
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